On three new species of Pteruchus THOMAS from the Triassic of Nidpur, M.P., India

Bhowmik, Nupur;Das, Neelam

Abstract

The present paper contains an account of three new species of the
corystosperm pollen organ Pteruchus from the Middle Triassic
beds of Nidpur, M.P. India. The new species P. glandulatus,
P. lobatus, and P. truncatus differ from each other in the nature
of central axis, disposition and length of the microsporophyll stalk,
angle of divergence of the stalk from the central axis, lobing of head
margin, number and shape of microsporangia per head and cuticular
details. In all the species, the central axis has square outline in
cross section and bears spirally arranged microsporophylls.

In P. glandulatus, the stalked microsporophylls appeared to
arise in low spirals from nodal regions leaving wide, naked internodal
areas. The central axis also shows secretory body like structures. In
P. lobatus, the microsporophylls are closely placed, short
stalked and borne almost at right angles to the central axis. The head
is hemispherical and has a deeply lobed margin. The pollen sacs are
cigar- shaped and contain bisaccate pollen grains in pollen
masses. In P. truncatus, the short stalked microsporophylls are
borne in low to high spirals on the central axis at angles ranging
between 45º90º.Theelliptical to orbicular head has an entire to
occasionally shallowly lobed margin and the pollen sacs are large,
banana-shaped with untapered truncated apices. The species of
Pteruchus described here are very different from all other
species so far reported from the Nidpur beds.